JPH06172967A - Boron nitride-containing film-coated base and its production - Google Patents

Abstract

PURPOSE:To obtain a boron nitride-contg. film-coated base excellent in adhesion by forming a mixed layer consisting of a film contg. a group VIa element and the atom constituting a base between the film and the base. CONSTITUTION:A film 2 contg a group VIa element and a film 3 contg boron nitride are successively formed on a base 1 to constitute the boron nitride-contg. film-coated base, and a mixed layer 4 contg. the constituent elements is formed between the base 1 and the film 2. The coated base is obtained by forming the film 2 by vacuum deposition or sputtering and ion irradiation. Since the mixed layer 4 is formed, a film enhanced in chemical activity and highly adhesive to the various bases is obtained. Further, the difference between the lattice constant and thermal expansion coefficient of a BN film to be formed on the film 2 is reduced, the induced internal stress is relieved in the BN film, and the adhesion of the BN film is maintained for a long period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boron nitride-containing film-coated substrate and a method for producing the same, and more particularly to a substrate coated with a boron nitride film for improving abrasion resistance, slidability, or chemical stability. The present invention also relates to a boron nitride-containing film-coated substrate having excellent hardness and adhesion of the film, and a method for producing the same.

[0002]

BACKGROUND ART Boron nitride (BN) has a cubic zinc blende type (c-BN), a hexagonal graphite-like structure (h-BN), or a hexagonal crystal depending on the crystal structure. Wurtzite type (w-BN) and the like. Among them, c-BN has high hardness second only to diamond and is excellent in thermal and chemical stability, so it has been applied to cutting tools such as those requiring wear resistance. It is used as a material for heat sinks by taking advantage of its insulating property and high thermal conductivity.
Although w-BN is also inferior in hardness to c-BN, it has a hardness and thermal conductivity superior to those of other nitrides.
Like N, it is expected to be used for the above applications.

However, c-BN and w-BN can be synthesized under high temperature and high pressure, and it has been difficult to synthesize the membrane at low temperature. In recent years, a method has been vigorously tried in which vacuum vapor deposition and ion irradiation are used in combination, the vaporized atoms are excited by collisions with the vaporized atoms, and the c-BN film can be synthesized even at low temperature by a non-thermal equilibrium process. became.

[0004]

However, c-BN, w
-BN has poor wettability with various substrates such as resins and metals, and when formed on a metal substrate, it has poor film adhesion and is difficult to be used practically. To compensate for this drawback, B
An intermediate layer made of a VIa group element is formed at the interface between the N film and the substrate, and the high chemical activity of the VIa group element is used to improve the adhesion of the BN film. Attempts are being made.

However, in the above method, although the adhesion strength of the film is improved, due to the difference in the lattice constant and the thermal expansion coefficient between the film made of the VIa group element and the BN film, the BN film formed on the film is The induced internal stress becomes high, which causes a drawback that the long-term safety of the adhesiveness of the BN film cannot be maintained. In view of the above problems, it is an object of the present invention to provide a boron nitride-containing film-coated substrate having excellent adhesion and a method for producing the same.

[0006]

According to the present invention, there is provided a boron-nitride-containing film-coated substrate in which a film containing a VIa group element is further coated with a film containing boron nitride.
Provided is a boron-nitride-containing film-coated substrate in which a mixed layer of the film containing the VIa group element and the atoms constituting the substrate is formed at the interface between the film containing the group a element and the substrate.

There is also provided a method for producing a boron nitride-containing film-coated substrate, which comprises forming a film containing a VIa group element by using vacuum vapor deposition or sputtering in combination with ion irradiation. The substrate used for the boron nitride-containing film-coated substrate in the present invention is not particularly limited, and any of those usually used as a substrate, for example, various metals, ceramics, resins and the like can be used. Further, as the film containing the VIa group element coated on this substrate, Cr, M
Examples of the film include a simple substance of o and W, an oxide, a nitride, and the like. Further, a film containing boron nitride is coated on the film containing the VIa group element. A mixed layer composed of atoms forming the film containing the VIa group element and the substrate is formed at the interface between the film containing the VIa group element and the substrate.

The film forming apparatus for carrying out the present invention is equipped with an evaporation source, an ion source and the like, and for example, the film forming apparatus as shown in FIG. 2 can be used. In FIG. 2, 1 is a substrate, 6 is a substrate holder, and 7a and 7
b is an evaporation source, 8 is an ion source, and they are vacuum vessels 9
It is housed inside. The vacuum container 9 is evacuated to a predetermined degree of vacuum by the exhaust device 12 and held. In addition, 7
The evaporation sources of a and 7b are for heating and vaporizing a substance containing a VIa or IVb group element and a boron-containing substance by an electron beam, resistance or high frequency, and other arbitrary method such as sputtering can be used. The method of the ion source 8 is not particularly limited, and a Kauffman type, a bucket type, or the like can be appropriately used. Also, the substrate holder 6
A film thickness monitor 10 capable of monitoring the vapor deposition amount of vapor deposition atoms on the substrate 1 and an ion current measuring device 11 capable of monitoring the irradiation amount of ions on the substrate 1 are provided in the vicinity. There is. The methods of the film thickness monitor 10 and the ion current measuring device 11 are not particularly limited. For example, a crystal oscillator is used as the film thickness monitor 10, and a Faraday cup or the like is appropriately used as the ion current measuring device 11. Can be used.

In carrying out the present invention, first, the substrate is placed in a substrate holder, housed in a vacuum container, evacuated to a vacuum degree of, for example, 1 × 10 ^-6 torr or less, and then the evaporation source is used.
The substance containing the VIa group element is vapor-deposited on the substrate by heating and vaporizing the substance containing the VIa group element. As the VIa group element-containing substance to be vaporized, Cr,
A simple substance of Mo or W, an oxide, a nitride, or the like can be used. Then, the substrate is irradiated with ions from an ion source simultaneously with the vapor deposition of the substance, alternately, or after the vapor deposition.

The ion species to be used may be an inert gas ion, a nitrogen ion, or a mixture of both, but in order to improve the wettability between the BN film and the film made of the VIa group element, nitrogen ion is used. It is preferable to use it to form a nitride of the film made of the VIa group element. However, in order to facilitate the formation of the mixed layer with the interface of the substrate, Ne, Ar, Kr, and X are initially formed in the formation of the film made of the VIa group element.
Ions having a large atomic weight, such as e ions, may be used, and nitrogen ions may be used near the surface of the film made of the VIa group element to improve the wettability with the BN film.

At this time, the acceleration energy of the irradiation ions is
There is no particular limitation, and it is appropriately selected in consideration of the heat resistance of the substrate.
It For example, in the case of a substrate with good heat resistance such as metal,
Acceleration energy of 2 KeV or more is used.
Acceleration energy is 2 for those with poor heat resistance such as fat.
It is preferable to use one having a KeV or less. Nitrogen ion
Or, the dose of irradiation with inert gas ions is
Nitrogen ions or inert gas ions in the formed film
1 x 10¹³Pieces / cm²Above 1 × 10²⁰Pieces / cm²Less than
It is preferable that Irradiation dose is 1 × 10¹³Pieces / cm²Not yet
When it is full, formation of mixed layer by ion irradiation is sufficient
Not 1 x 10²⁰Pieces / cm ²If more than
It is preferable because it will cause excessive damage to the film and substrate due to irradiation.
Absent.

Further, the ratio of the number of atoms of the VIa group element to the number of irradiated ions when forming the film made of the VIa group element is not particularly limited. For example, when a substrate such as the above resin is used, the acceleration energy of the ions to be irradiated must be made small, so that the thickness of the mixed layer of the film / substrate interface made of the VIa group element cannot be made large. In such a case, and when irradiating with nitrogen ions, the film /
The number of VIa group element atoms increases at the substrate interface, and the high chemical activity of these elements is used to increase the adhesion strength and reduce the difference in the lattice constant and the thermal expansion coefficient with the BN film near the film surface. Therefore, the number of nitrogen atoms contained in the film may be increased.

Further, the film thickness is not particularly limited, but it is preferably formed to be about 5 nm to 1000 nm. If it deviates from this range, the effect on the adhesiveness of the film will not be sufficiently exerted. Further, in the present invention, after the above steps, a film containing boron nitride (BN) is formed on the film. The method in this case is not particularly limited, but, for example, it is formed by using the same apparatus as that used for forming the film containing the VIa group element, that is, the method using vacuum vapor deposition or sputtering and ion irradiation in combination. In this case, the BN-containing film can be formed without taking out the substrate from the vacuum container, which is a preferable method because a method of forming a film can be performed with less impurities mixed into the film or a film forming step.

Specifically, in forming the BN film, after forming the film containing the group VIa element,
Without taking it out of the vacuum container, a substance 14 containing a boron element, such as a simple substance of B, an oxide or a nitride, is vacuum-deposited on the substrate from the evaporation source while keeping the vacuum inside the vacuum. At the same time, alternately or after film formation, the substrate is irradiated with ions from the ion source.

At this time, the acceleration energy of the irradiation ions is not particularly limited and is appropriately selected in consideration of the heat resistance of the substrate. For example, in the case of a substrate having good heat resistance such as metal, one having an acceleration energy of 2 KeV or higher is used, and for example, a resin such as a resin having poor heat resistance has an acceleration energy of 2 KeV or less. The ion species used at this time are inert gas ions, nitrogen ions, or a mixture of both. Inert gas ions are
By the collision of the evaporated B atom and the inert gas ion,
The B atom is further excited, which is advantageous for the formation of c-BN.

Further, when forming the boron nitride-containing film, the ratio of the number of B atoms reaching the substrate to the number of nitrogen ions (B /
The N transport ratio) is not particularly limited, but is preferably 0.5 or more and 40 or less. If it is less than 0.5, the sputtering of B atoms by ions becomes excessive, a film is not formed, and 40
If it exceeds the range, boron that does not bond with nitrogen is excessively contained in the film, and the characteristics of the film are deteriorated, which is not preferable.

Further, since ion irradiation is used when forming the film containing BN, a mixed layer composed of both constituent atoms is formed at the interface between the film containing the VIa group element and the film containing BN. Since it is formed, the adhesion between the film containing the VIa group element and the film containing BN is good. In addition, in the present invention, when a substrate for which thermal damage must be extremely avoided is used, it is preferable to perform film formation while cooling the substrate holder with water.

[0018]

According to the boron nitride-containing film-coated substrate of the present invention,
A boron nitride-containing film-coated substrate in which a film containing boron nitride is further coated on a film containing a Group VIa element,
The VIa at the interface between the film containing the VIa group element and the substrate.
Since the mixed layer including the film containing the group element and the atoms forming the substrate is formed, a film having high chemical activity and excellent adhesion to various substrates is formed, and the BN film and the substrate are formed. The adhesiveness with is remarkably improved. That is, the difference in the lattice constant and the thermal expansion coefficient between the VIa group element and the BN film formed on the film is relaxed, the internal stress induced in the BN film is reduced, and the adhesion of the BN film is reduced. The long-term safety of is secured.

Further, since the film containing the group VIa element is formed by using vacuum vapor deposition or sputtering in combination with ion irradiation, the irradiated ions collide with the vapor deposition atoms and push the vapor deposition atoms into the substrate, or Repels the constituent atoms. Therefore, a mixed layer composed of the constituent atoms of the substrate and the film is formed at the interface between the substrate and the film made of the VIa group element, and as a result, it is superior to the substrate using the chemical activity. A film having excellent adhesion can be obtained.

[0020]

EXAMPLE A boron nitride-containing film-coated substrate according to the present invention is
As shown in FIG. 1, a film 2 containing a VIa group element and a film 3 containing a boron nitride are sequentially formed on a substrate 1, and those films between the substrate 1 and the film 2 containing a VIa group element are The mixed layer 4 containing the constituent elements is formed.

Hereinafter, a method for manufacturing a substrate coated with a boron nitride-containing film will be described. Example 1 A high-speed tool rope (SKH51) was manufactured using the apparatus shown in FIG.
The base body 1 made of is placed on the base body holder 6 and 1 × 10 ⁻⁶
The vacuum container 9 was held at a vacuum degree of torr. Then purity 9
9.999% Cr pellets are vaporized using an electron beam evaporation source 7a to form a Cr film which is a film 2 containing a VIa group element on a substrate 1, and at the same time, a nitrogen gas having a purity of 5N is supplied to an ion source 8 in a vacuum container. It is introduced until it becomes 5 × 10 ⁻⁵ torr in 9 and is ionized in the ion source 8 and 10K is applied to the substrate 1.
Irradiation was performed with an acceleration energy of eV. At this time, the evaporation amount of atoms and the irradiation amount of nitrogen ions were adjusted so that the Cr / N composition ratio was 3/1. As the ion source 8, a bucket type ion source using a cusp magnetic field was used.

After forming a film of Cr-N element to a thickness of 50 nm in this manner, boron pellets having a purity of 99.7% are vaporized by using the electron beam evaporation source 7b to form a boron film on the substrate 1. At the same time, nitrogen gas having a purity of 5N was introduced into the ion source 8 until the inside of the vacuum container 9 became 5 × 10 ⁻⁵ torr, ionized, and the substrate 1 was irradiated with an acceleration energy of 0.5 KeV. At that time, the evaporation amount of boron atoms and the irradiation amount of nitrogen ions were adjusted so that the B / N composition ratio was 1, and the boron nitride-containing film 3 was formed to a film thickness of about 1 μm.

Example 2 After placing the same substrate 1 as in Example 1 on the substrate holder 6,
It was placed in a vacuum container 9, and the container 9 was kept at a vacuum degree of 1 × 10 ⁻⁶ torr or less. After that, Cr pellets having a purity of 99.999% are vaporized by using the electron beam evaporation source 7a, and VI pellets are formed on the substrate 1.
At the same time as forming the Cr film that is the film 2 containing the a-group element, nitrogen gas having a purity of 5N is introduced into the ion source 8 until the inside of the vacuum container 9 becomes 2 × 10 ⁻⁵ torr, and the ion source 8 is supplied. It was ionized and the substrate 1 was irradiated with an acceleration energy of 2 KeV. At this time, the atomic evaporation amount and the nitrogen ion irradiation amount were adjusted so that the Cr / N composition ratio was 5/1.

After forming a film of Cr-N element to a thickness of 100 nm in this manner, a boron nitride-containing film 3 was formed to a thickness of about 1 μm as in Example 1. Example 3 After placing the same substrate 1 as in Example 1 on the substrate holder 6,
It was placed in a vacuum container 9, and the container 9 was kept at a vacuum degree of 1 × 10 ⁻⁶ torr or less. After that, Cr pellets having a purity of 99.999% are vaporized by using the electron beam evaporation source 7a, and VI pellets are formed on the substrate 1.
A Cr film, which is a film 2 containing an a-group element, was deposited by 50 nm. After that, nitrogen gas having a purity of 5N is introduced into the ion source 8 until the inside of the vacuum container 9 becomes 2 × 10 ⁻⁵ torr, and the ion source 8
It was ionized inside, and the substrate 1 was irradiated with acceleration energy of 20 KeV. The dose of ions at this time is 1 × 10 ¹⁶
The number was pieces / cm ² . Next, the boron nitride-containing film 3 was formed on the film made of the Cr—N element to have a film thickness of about 1 μm as in Example 1.

Comparative Example 1 After placing the same substrate 1 as in Example 1 on the substrate holder 6,
It was placed in a vacuum container 9, and the container 9 was kept at a vacuum degree of 1 × 10 ⁻⁶ torr or less. After that, boron having a purity of 99.99% is vaporized by using the electron beam evaporation source 7a to deposit a boron film on the substrate 1, and at the same time, nitrogen gas having a purity of 5N is supplied to the ion source 8 in the vacuum container 9 at 2 × 10 ^−5. It was introduced until it reached torr, ionized in the ion source 8, and the substrate 1 was irradiated with an acceleration energy of 0.5 KeV. At this time, the atom evaporation amount and the nitrogen ion irradiation amount were adjusted so that the B / N composition ratio was 1/1. The other methods of forming the BN film were the same as in Example 1.

The hardness of the film was measured by the Vickers hardness under a load of 5 g for the substrate on which the film was formed in Examples 1 to 3 and Comparative Example 1 above. Further, with respect to the film-coated substrate, the adhesion strength of the film was measured by a scratch tester with an AE sensor, and the results are shown in Table 1. Adhesion is
While continuously increasing the load from ON with a diamond indenter, the film is scratched, and the load at which the AE signal that is monitored suddenly rises is taken as the film peeling load, and the adhesion strength is expressed by the magnitude of the load. .

[0027]

[Table 1] As is clear from the table, both the examples and the comparative examples had excellent hardness, but the BN film of the comparative example was inferior to the film adhesiveness of the example.

[0028]

According to the present invention, there is provided a boron-nitride-containing film-coated substrate in which a film containing a VIa group element is further coated with a film containing a boron nitride. Since a mixed layer consisting of the film containing the VIa group element and the atoms constituting the substrate is formed at the interface with the substrate, a film having high chemical activity and excellent adhesion to various substrates is obtained. In addition, the adhesion between the BN film and the substrate is significantly improved. That is, the difference in the lattice constant and the thermal expansion coefficient between the VIa group element and the BN film formed on the film is relaxed, the internal stress induced in the BN film is reduced, and the adhesion of the BN film is reduced. The long-term safety of can be secured.

Further, since the film containing the VIa group element is formed by using vacuum vapor deposition or sputtering in combination with ion irradiation, the irradiated ions collide with the vapor deposition atoms and push the vapor deposition atoms into the substrate, or Repels the constituent atoms. Therefore, a mixed layer composed of the constituent atoms of the substrate and the film can be formed at the interface between the substrate and the film composed of the VIa group element, and as a result, the mixed layer can be formed on the substrate more than that utilizing the chemical activity. On the other hand, a film having excellent adhesion can be obtained.

Therefore, the boron nitride-containing film coating having high hardness and excellent slidability is improved in performance such as friction, wear and lubrication performance of a substrate such as a cutting tool, a mold, a magnetic head or various sliding parts. It becomes possible to obtain a substrate.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a boron nitride-containing film-coated substrate according to the present invention.

FIG. 2 is a schematic cross-sectional view of a main part of a film forming apparatus used when manufacturing a boron nitride-containing film-coated substrate of the present invention.

[Explanation of symbols]

 1 Substrate 2 Film containing VIa group element 3 Boron nitride-containing film 4 Mixed layer

Continued Front Page (72) Inventor Kiyoshi Ogata 47 Umezu Takaunecho, Ukyo-ku, Kyoto City Nissin Electric Co., Ltd.

Claims (2)

[Claims] 1. A boron nitride-containing film-coated substrate in which a film containing a group VIa element is further coated with a film containing a boron nitride, wherein the interface between the film containing the group VIa element and the substrate is A boron nitride-containing film-coated substrate, wherein a mixed layer composed of a film containing a VIa group element and atoms forming the substrate is formed. 2. The method for producing a boron nitride-containing film-coated substrate according to claim 1, wherein the film containing a VIa group element is formed by using vacuum vapor deposition or sputtering in combination with ion irradiation.